Introduce EntityParserOutputGenerator

The tests which got removed in this patch are either moved to one of the
ReferencedFinder classes or moved to EntityParserOutputGeneratorTest.

This patch also includes lots of refactoring of the EntityView and moves
too much code into the EntityContent class. Therefore, a follow up change
will intorduce an EntityParserOutputGeneratorFactory to handle this code
in a saner way.

Furthermore, even more bindings, eg. to fingerprints etc. will be moved out
of EntityView. We will then perhaps need different factory classes for
items and properties.

Sorry guys, this patch has grown a bit... Lots of kudos to whoever will
review this.

Change-Id: I60bc79b90cb53bf40ddb8e0578776771cda76f48
Merge "Introduce EntityParserOutputGenerator"